doral330

Alright so recently after the Jeep warms up to operating temp, I'd shut it off and come back in about 5 minutes or so and I'll start it up and it will idle really low and stumble. Kind of like a misfire. I had a CEL come on and I got a misfire on cylinder 3. Also when it does this I have to put my foot to the floor and the RPM's slowly come up but it sounds like something is banging or cracking. So my question is why is it stumbling? What is the banging or popping noise? What do I need to do to diagnose this problem?

Thanks guys

01 Cherokee sport

scottmphoto

It could be a heat soak issue. My '91 used to do this until I completely went through the cooling system and took out the under hood insulation pad.

salad

That's very typical for 2001s. Chrysler released a TSB on heat soak for this issue. What happens is that when you shut the engine off, the fans are no longer moving air around, nor is the fuel moving; so heat from the catalytic converters in the exhaust manifold rises and boils the fuel in the injectors and fuel rail. Jeep runs like crap until you get the vaporized fuel out or until you let it cool down completely.

The official fix is to insulate the fuel rail and injectors with heat wrap. It's a sticky foil-like substance, you can find at part stores.

doral330

Alright I wrapped all the injectors and the entire rail. Hopefully that does the trick. Thanks for the help

tjwalker

It does sound like heatsoak. That TSB fix from Jeep works for some (mild heatsoak) but doesn't work for others.

Some guys end up putting a timer on the e-fan so that it runs for a preset time after you turn the key off to reduce under the hood temps. Others actually cut louvers into the hood for severe cases. NAXJA has a few threads on these things if you are so inclined.

freegdr

Theres also a small heat shield that can be add to block heat from warming injectors...http://bleepmicro.livejournal.com/57852.html

doral330

I actually already have that and it's falling apart. I'm sure it worked for a while but I hope this fuel rail tape sticks better and keeps it all nice

freegdr

Its falling apart and issues are starting ....Think theres a clue here.